• Clinics in Shoulder and Elbow
• /
• v.3 no.2
• /
• pp.95-101
• /
• 2000

Purpose : The purpose of this study was to evaluate the efficacy of oblique coronal MR images, oblique axial images of neutral, internal rotation and external rotation positions in the diagnosis of SLAP Ⅱ lesion. Materials and Methods: MR arthrography of the glenohumeral joint was evaluated retrospectively in 16 patients(16 shoulders) who underwent arthroscopic surgery(mean age; 38 years old, Male; 13, Female; 3). Oblique coronal fat-suppressed Tl-weighted spin echo images were performed with each shoulder in the neutral position of the arm and oblique axial images were performed in neutral, internal and external rotations of the arm respectively. The preoperative findings of MR were classified as definite tear, possible tear and no tear. Arthroscopic findings were correlated with MR findings of several different position of the arm. Results: Arthroscopic surgery revealed 8 SLAP Ⅱ lesion, 2 SLAP I lesion, and 6 normal superior labrum respectively. The accuracy of diagnosis in the 8 SLAP Ⅱ lesion were high on oblique axial image in external rotation which were interpreted as 8 definite tear, to compare with oblique axial images in neutral position which were interpreted as 4 definite tear, 3 possible tear, 1 no tear. The 6 normal superior labrum lesion were interpreted as no tear in all three position. The 2 SLAP I lesion were interpreted as 1 definite tear, 1 no tear on oblique axial image in neutral position and 1 definite tear, 1 possible tear on oblique axial image in external rotation. Conclusion: This study showed that axial MR images in external rotation of the arm combined with oblique coronal images have proved to be effective to detect SLAP Ⅱ lesion, and should be considered in imaging protocol for MR arthrography of the SLAP Ⅱ lesion.

• Analytical Science and Technology
• /
• v.10 no.1
• /
• pp.66-74
• /
• 1997

Influence of the axial dispersion on immobilized enzyme catalytic bed was investigated in order to examine the kinetic behavior of the biocatalysis. The enzyme employed in this study was the tyrosinase(EC 1.14.18.1) immobilized on carbon support : this system requires two substrates of phenol and oxygen. This enzyme has potential application for phenol degradation in waste water. A simulated reactor was a packed-bed reactor of 2.54cm in diameter and 10cm long, loaded with the immobilized carbon particle with an average diameter of $550{\mu}m$. A phenol feed in the strength of 55.5mM(5220ppm) was used to observe the behavior of the immobilized enzyme column at three different dissolved oxygen levels of 0.08445mM(2.7ppm), 0.1689mM(5.4ppm) and 0.3378mM(9.5ppm) with the flow rates in the range of 60(1mL/s) to 180mL/min(3mL/s). Examination of the Biot number and Damkolher numbers of the immobilized system enables us to eliminate the contribution of external mass transfer to set of differential equations derived from the dispersion model. Solution of the equation was finally obtained numerically with the application of the Danckwert boundary conditions and the assumed zero-and first order rates on the non-linear two substrate enzyme kinetics. Higher conversion of phenol was observed at the low flow rates and at the higher oxygen concentration. Comparison of axial dispersion and plug flow model showed that no detectable difference was observed in the column outlet conversion between the axial and the plug flow models which was in complete agreement with the previous studies.

• Journal of Biomedical Engineering Research
• /
• v.20 no.4
• /
• pp.409-417
• /
• 1999

Talairach atlas consists of three orthogonal sets of coronal, sagittal, and axial slices. This atlas has recently an important role as a standard brain atlas in diagnosing disease related with brain function and analyzing cause of brain disease. The 3D digital volume data set reconstructed from the atlas is widely applied to visualization and quantitative analysis of results processed in the digital computer. This paper represented application method of bi-linear interpolation technique, proposed tri-planar interpolation algorithm for 3D volume data reconstruction of Talairach atlas. And we implemented Talairach atlas editor and discussed problems in volume reconstruction of Talairach atlas. The bi-linear method was applied to only one set of the slices and considered the on intensity value in the interpolation process. The tri-planar technique concurrently uses three orthogonal sets of slices with the same information of brain structures. Talairach atlas editor visualized three sets. of atlas slices on the same coordinate and had editing function. Using the atlas editor, we represented problems in volume reconstruction by showing inconsistency of brain structures among three sets of atlas slices.

• Journal of the Optical Society of Korea
• /
• v.13 no.2
• /
• pp.184-192
• /
• 2009

There are total eight degrees of freedom in designing a three-mirror system. If we correct four kinds of third order aberrations and the system should have the specified effective focal length, the remaining three degrees of freedom can be used for selecting a suitable configuration for a specific application. We suggest an analytic design procedure for a three-mirror telescope system which has a suitably sized secondary mirror and proper separations between mirrors, and is corrected for four kinds of third order aberrations, spherical aberration, coma, astigmatism, and field curvature. Two design examples are shown. One has a compact configuration with off-axial field, the other has relatively long configuration with annular ring field.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.128-131
• /
• 2011

Management of indoor air quality of underground subway station is an important issue. The air handling unit (AHU) installed in the underground subway station is the main facility determining the air quality of station. Especially for removing particulate matters, it is important to operate the appropriate air filter. In this study, we studied particle collection efficiency of axail-flow cyclone for subway AHU. The particle collection efficiencies of axial-flow cyclones with three different outlet shape have been evaluated.

• Journal of Magnetics
• /
• v.21 no.3
• /
• pp.437-441
• /
• 2016

Dipole model based analytical expression is proposed to estimate the length and depth of the rectangular defect on ferromagnetic pipe. Among the three leakage profiles of Magnetic Flux Leakage (MFL), radial and axial leakage profiles are considered in this work. Permeability variation of the specimen is ignored by considering the flux density as close to saturation level of the inspected specimen. Comparing the profile of both the components, radial leakage profile furnishes the better estimation of defect parameter. This is evident from the results of error percentage of length and depth of the defect. Normalized pattern of the proposed analytical model radial leakage profile is good agreement with the experimentally obtained profile support the performance of proposed expression.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.8
• /
• pp.1081-1088
• /
• 2003

Numerical investigation on the structures of various Taylor vortices induced in the flow between two concentric cylinders, with the inner one rotating and with a pressure-driven axial flow imposed, is carried out, and compared with the experiments of Wereley and Lueptow [Phys. fluid, 11(12), 1999] who studied the Taylor vortices using PIV in detail. Especially, the properties of helical vortices and random wavy vortices are discussed, and their three-dimensional structures are visualized using the numerical data. Our simulation also predicts that random wavy vortices have quasi-periodic movement which can be explained by traveling waves formed in the azimuthal direction. The numerical results are well consistent with the experimental findings of Wereley and Lueptow.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.30 no.7 s.250
• /
• pp.622-629
• /
• 2006

The shape optimization of blade sweep in a transonic axial compressor rotor of NASA Rotor 37 has been performed using response surface method and the three-dimensional Wavier-Stokes analysis. Two shape variables of the rotor blade, which are used to define the rotor sweep, are introduced to increase the adiabatic efficiency of the compressor. Throughout the optimization, optimal shape having a backward sweep is obtained. Adiabatic efficiency, which is the objective function of the present optimization, is successfully increased. Separation line due to the interference between a shock and surface boundary layer on the blade suction surface is moved downstream for the optimized blade compared to the reference one. The increase in adiabatic efficiency for the optimized blade is caused by suppression of the separation due to a shock on the blade suction surface.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.833-838
• /
• 2001

The objectives of this study are to investigate effective stiffness of circular reinforced bridge columns and to provide reasonable effective stiffness equations for seismic design to the current Korean Bridge Design Standard. The material nonlinear analysis was conducted for 5184 columns of which variables were the concrete compressive stress, the steel yielding stress, the longitudinal steel location parameter, the longitudinal steel ratio, the axial load level, and the diameter of section. The current Korean Bridge Design Standard generally used the gross section stiffness because of unclear provision, it may be non-conservative because of being evaluated greater design seismic force and less design displacement than those of the abroad provision. Therefore, the proposed effective stiffness equations include three variables such as : the longitudinal steel location parameter, the longitudinal steel ratio, and the axial load ratio. Two equations of effective stiffness are proposed which may be used for earthquake force estimation and for earthquake displacement estimation, respectively.

• International Journal of Automotive Technology
• /
• v.8 no.4
• /
• pp.455-465
• /
• 2007

The bushing element shows nonlinear characteristics in both displacements and frequencies, also with hysteretic responses for repeated vibrational excitations. Since the characteristics of the rubber bushing significantly affects the accuracy of the vehicle dynamic simulation result, it should be accurately modeled in the vehicle suspension model. To develop an accurate bushing model for vehicle dynamics analysis, the bushing characteristics under several excitation inputs must be known. In this paper, a 3-axis tester was used to capture the bushing characteristics. The random inputs, sine inputs, and step inputs were imposed on each axis of the bushing. Also, two-axis inputs, the radial-axial and radial-normal inputs, were simultaneously imposed on the tester. Three-axis inputs including the radial-axial-normal direction were supplied to the tester. Bushing characteristics of each case were precisely analyzed. These results could be available for dynamic modeling of bushing.